Despite the relative consensus on the benefits of pre-surgical weight loss, i.e., the reduction of comorbidities associated with surgical act, such as decreased visceral fat, liver volume, hemorrhage perioperative and surgical time, the characteristics of the diet to be employed in this period need to be defined more clearly. As there is no description of comparative studies on diet of normal consistency, using solids and liquids, there are doubts as to the real need for consistency liquid diet in preoperative bariatric surgery. The lack of robust evidence has made nutrition professionals adopt different procedures. There is still a belief that these patients are unable to lose weight in the preoperative period, the ongoing history of previous attempts without success.